Hypodermic injection system

ABSTRACT

A hypodermic injection system particularly for use in mass immunizations having a handpiece with a grasping mechanism for holding ampules filled with injectate, a plunger for driving into the ampule to discharge the injectate in an injection process, an injection spring mechanism for driving the plunger, a motor and/or manual mechanism for cocking the injection spring mechanism, and an ampule ejection mechanism for ejecting ampules after use under control of a release mechanism. Ampules can be loaded, used and ejected without contact by the user of the system or the patient being injected. Also disclosed are a filling station for filling ampules through their injection orifices, and an arming device for setting the injection spring. Ampules are disclosed having a piston which is drivable towards an orifice to discharge injectate through the orifice. Ampules are also disclosed having enlarged proximal portions for easy grasping by the grasping mechanism of the injector. Ampules are further disclosed with separators for mixing lyophilized medication and a diluent. Further disclosed are magazines for holding ampules for sequential use by the hypodermic injector. The disclosed system finds particular use as a mass immunization kit for making numerous injections in the field.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of U.S. patent application Ser. No.10/224,034 filed Aug. 20, 2002, and claims the benefit of U.S.provisional patent applications Ser. No. 60/313,978 filed Aug. 21, 2001and Ser. No. 60/358,861 filed Feb. 22, 2002.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to hypodermic injection systems, and inparticular to those residing in a kit format. It more particularlyrelates to hypodermic injection systems in kit form for massinoculations, using electrical or manual power. The inventionadditionally relates to hypodermic injection systems having ampules thatare processed to avoid cross contamination.

2. Description of the Prior Art

Many forms of hypodermic injection systems are available. These systemsinclude rapid delivery of vaccines/medications with jet injectors thatutilize the same orifice for every injection, and in some cases, useindividual, single use ampules that must be handled by the vaccinatorwhen filling them with vaccine and/or when inserted or removed from theinjector. Some are manually armed, these to include all personal useinjectors now available, and some have other means of power such ascompressed gas. None of the injection systems are available in kit formthat will provide healthcare workers with everything needed to deliverthousands of shots in remote or urban locations before returning to acentral location for an equipment re-supply or re-energizing the powersources, and none supply single use, self-destruct ampules in a magazineformat that can also be used as a shipping container, or if needed, as amixing structure for the simultaneous preparation of numerouslyophilized filled ampules.

Elements of this disclosure that were considered in earlier patents byat least one of the present inventors are: (1) one ampule per injectionfound in U.S. Pat. No. 5,080,648, (2) the magazine concept for holdingampules while connected to the injector, and a guard ring around theampule to discourage splashing are found in U.S. Pat. No. 5,318,522, (3)inserting new ampules and/or discarding used ampules without the need ofany physical contact by the user, and also the arming station forcompressing an energy storage spring in the hand piece are found in PCTapplication Serial No. PCT/US00/07470, and (4) perforator (ormini-needle) delivery for reduced pressure and pain to the patient isfound in U.S. Pat. No. 6,056,716. One of the present inventors has apending patent application directed to a structural containment of lowcost syringes used at high pressure. Elements from each of the fourpatents are discussed in the present disclosure for mass immunizationsystems, clinical injectors, and personal use injectors, and theinvention herein will represent improvements or new ways for performingthese vital functions for all types of injection systems. The latterpatents are all incorporated herein by reference.

The invention in its preferred form provides the equipment needed for anelectrically powered injection kit, including enough battery power forthousands of injections without means of support required from a centrallocation or conventional sources of power. The basic means of energizingthe injector is electrical power; however, as a user option, the kit andinjection devices preferably also include a means for manual operationto assure continuation of the injection procedure if the transportablepower sources are depleted and/or a source of renewable power is notavailable. The risk of cross-infection is avoided with disposable,single use, self-destruct ampules (also referred to as cartridges,capsules, vials, etc.) that are designed to interface with the injectorin such a way that user contact with the ampules both before and afterthe injection is unnecessary. In addition, with respect to the preferredembodiment, the trigger is disabled until the ampule is securely held inplace with the combination of a grasping jaw assembly and a lockingsleeve to prevent the possibility of an ampule becoming a projectilewhen the injection ram is released. The ampules can be pre-filled by themanufacturer with liquid or lyophilized medication, or can be filled onsite if necessary. Also included in the kit are magazines that holdnumerous ampules before re-supply is needed. These magazines aredesigned for rapid, sterile delivery when used with the injector. Insome cases, the magazine also serves as the shipping container for theampules, and has the capability of simultaneous, on site mixing of thelyophilized filled ampules when needed. Alternatively, a filling stationprovides an efficient and sterile means for filling the ampules withliquid or lyophilized medication just prior to delivery.

The method for non-contact changing of ampules has utility for clinicalsituations and personal use injections as well, where avoiding the riskof cross infection to healthcare workers is critically important whendealing with patients harboring dangerous pathogens. By the same token,where the risk of cross infection is not a factor, such as patientsreceiving insulin, or perhaps the daily delivery of growth or otherhormone injections, the patient or healthcare worker assisting them caneasily handle the ampule for both insertion and removal with the novelgrasping system disclosed. The availability of this system has specialutility for people who find the prior art techniques for filling theampule and manually arming personal-use injectors to be physicallychallenging, if not impossible, in some cases.

For all of the injection scenarios discussed, very short perforators (1to 2 mm) as the exit nozzle, and used for piercing the injection siteprior to jet delivery, are included in the preferred embodiment becausethey allow for low pressure injections (200 to 1,000 psi) as opposed totypical jet injection pressures on the order of 2,000 to 3,500 psi ormore. Properly contained ampules, as discussed in the pending U.S.patent application referred to above, open the door formanufacturer-modified insulin and other syringes having 27 or 28 gaugeneedles that are already produced by the hundreds of millions, whichwhen supplied at perforator length will provide an injection orifice onthe order of 0.008 or 0.007 inches, which are typical diameters for jetinjection systems. The economy of this approach is quite substantial

SUMMARY OF THE INVENTION

The object of this invention is to provide a new, high-speed injectionsystem that is economical, technically suited to campaigns for massimmunization and meets the needs of reliability, ergonomics, poweravailability, cost, safety and effective injections. The system isdesigned with several options for both powered and manual operation sothat the needs of a wide variety of users can be met, these to includeclinical and personal use injection systems. One option for powering theinjector is an embodiment wherein a motor is remote from the handpiecediscussed below, and referred to as a “Motor-Off Tool” (MOT) “Handpiece”with three methods including both electrical and manual means forcompressing the injection spring. Also available is another embodimentwherein a motor is included in the handpiece, and referred to as a“Motor-In-Tool” (MIT) “Handpiece” similar to that reported in earlierdisclosures by at least one of the inventors; however, according to apreferred embodiment in this disclosure, rather than a rotating cammechanism for compressing the energy storage spring, a gear reductionand ball screw are used to do the same thing which provides novelmethods and advantages for operating the motor in both the forward andreverse directions. For example, motor reversal allows for increasingthe speed of rapid, repetitive injections by compressing the injectionspring in one direction and then reversing direction for an immediatereturn to the starting point in preparation for the next arming cycleregardless of whether or not the present injection is delivered. Aninternal switching arrangement determines when the motor drive reachesthe intended location, then provides an appropriate signal to firststop, latch the spring, and then reverse motor direction at theappropriate time. This sequence of repeated motor reversal takes placefor every injection cycle, the distance of travel in each directionbeing determined by the volume of injectate to be delivered. In everycase described, the mass immunization kit will also include a means formanual delivery if necessary; and this system has utility as a manualdevice for clinical situations.

In an alternate embodiment, the forward direction of the motor allowsfor the ball screw drive to completely eliminate the energy storageinjection spring by using a direct drive delivery from the motor to theampule piston. One of the advantages of direct drive is the ability toprovide an ever-increasing drive voltage to the motor that, in turn,will yield a profile of increasing pressure over the course of aninjection. This increasing pressure will drive the injectate everdeeper, rather than ever more shallow, which will discourage theinclination of medication being left on the surface as is sometime seenwith the usual spring driven, orifice oriented systems. This feature isespecially useful for personal use injectors used by diabetics who areoften very sensitive to the correct amount of insulin entering the body.Availability of reversing motor direction can also be used for fillingan empty ampule, and has particular utility with personal use injectorsas an improvement to the tedious manual methods now in use. To do this,the injector ram will first grab the plunger of an empty in-dwellingampule, and then, with a push button command by the user, the injectorwill pull the plunger back to draw vaccine from a supply connected tothe front end of the ampule. Mechanical or magnetic means can be used tomake this connection to the ampule piston. Once the ampule is full byvirtue of the reverse direction, a low speed button controlled motordrive will allow the vaccinator to slowly “jog” the piston forward, andvisually determine when all air is expelled from the ampule. For directdrive delivery, the motor is then transferred to its high-speed mode todrive the injectate into the injection site.

The ampules are designed for interfacing with a circular set of graspingjaws on the front of the injector. In one embodiment, the systemcomprises the following: (1) the ampules are packaged on a tear-awaypaper strip, (2) a filling station fills the ampules with pre-mixed,liquid vaccine while attached to the strip, (3) two different magazineoptions are available that house the ampules for rapid, easy insertioninto the magazine, and then, one by one into the injector, (4) theinjection is followed by self-destruction of used ampules, (5) twodifferent handpiece options (the choice depending on usercircumstances), and (6) several options for compressing the spring. Thehigh-speed manual option mentioned earlier is an especially importantfeature for financially strapped countries that are unable to affordhigher-level injection systems. The primary means for arming theautomatic injector is electrical power for energizing a motor thatserves to compress an injection spring. It should be noted that thespring-energized injector options are virtually always adaptable tomanual operation as either a primary or emergency back-up system. Thisoption is not available with conventional compressed gas, CO₂ orignitable gas drive systems.

Also disclosed are means for an on site mixing of pre-filled individualampules having lyophilized medication in one compartment, and its mixingdiluent in a companion compartment, the two being separated by anappropriate barrier. Several means are shown for utilizing a barrierbetween the medication and its diluent. The barrier can be frangible ora one-way valve. In one embodiment, a filling station will providesufficient force for filling the individual ampules with pre-mixedliquid vaccine through the exit nozzle, an option that is also usefulfor the personal use injectors described above. This approach for frontend filling will virtually eliminate the problem of having air enter thechamber that usually occurs when filling ampules by creating a vacuumwhen drawing back on the plunger. Alternatively, the filling station canprovide sufficient force to insert the diluent through the exit nozzleand then mix it with lyophilized medication located in the ampule.

A new concept of a mixing magazine allows for simultaneous, on-sitemixing of an entire magazine full of the pre-filled, lyophilized/diluentcartridges. In this case, the magazine can also be used as the shippingcontainer from the manufacturer to anywhere in the world thus, ofcourse, lowering cost and further reducing the risk of contamination dueto intermediate handling.

In summary, the system includes a transportable injection station or kitthat is easily moved from place to place by foot, bicycle, motorscooter, motorcycle, water, air transport or whatever means is availablefor moving people and equipment to an immunization site. If no otherworking surface is conveniently available at the site, legs provided aspart of the station are opened and extended to the proper height for theuser, and optional flat panels from one to all of the four sides of thehousing are extended to form a working surface if needed. When the kitis opened, the healthcare worker will have everything needed forthousands of injections without any other means of support for theamount of time expected at the location. As mentioned above, the kitwill include magazines of the selected type, filling station if needed,enough battery power to provide the number of shots expected, and amodule for manually arming the injector in the event that all batterypower is unexpectedly depleted, and/or the power needed for rechargingthe batteries is not available.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a pictorial view of a portable injection system or kitaccording to the invention;

FIG. 2 is a partially exploded, pictorial view of one embodiment of theinvention having a motor off the tool;

FIG. 3 is a pictorial view of a mechanical arming system for use withthe embodiment shown in FIG. 2;

FIG. 4 is a pictorial view of an electrical or optionally manual armingstation for compressing an injection spring in the embodiment shown inFIG. 2;

FIG. 5 a is a pictorial view of a Motor-In-Tool injector having aremovable motor and battery module for arming the Motor-In-Toolembodiment of the invention;

FIG. 5 b is a pictorial view of a motor-In-Tool injector having aremovable motor module for the Motor-In-Tool embodiment of theinvention;

FIG. 5 c is a pictorial view of a removable, back-up manual-armingmodule for the Motor-In-Tool embodiment of the invention;

FIG. 6 a shows a permanent Motor-In-Tool injector according to theinvention, in pictorial form;

FIG. 6 b is a cut-away view of the Motor-In-Tool injector illustrated inFIG. 6 a, showing its internal mechanism;

FIG. 7 a is a cut-away view of a second injector for the embodiment ofthe Motor-In-Tool invention depicted in FIG. 6 a, showing its internalmechanism in its armed condition;

FIG. 7 b is a partly cut-away front view of the injector shown in FIG. 7a also showing the internal mechanism in its armed condition;

FIG. 7 c is a cut-away side view of the injector shown in FIG. 7 ashowing its internal mechanism in its fired or unarmed condition.

FIG. 7 d is a cut-away front view of the injector shown in FIG. 7 cshowing its internal mechanism in its fired or unarmed condition.

FIG. 8 a is a cut-away view of a version of an injector for the firstembodiment of the invention for the Motor-Off-Tool injector shown inFIG. 2 with an ampule illustrated with a perforator at the exit port;

FIG. 8 b is an enlargement of the ball transfer subsystem shown in FIG.8 a

FIG. 8 c is an enlargement of the jaw structure for grasping ampules asshown in FIG. 8 a;

FIG. 8 d is an illustration of one embodiment for self-destruction of aperforator after use in FIG. 8 a;

FIG. 9 is a pictorial view of a used ampule being ejected from the jawstructure shown in FIG. 8 c;

FIG. 10 a is a pictorial view of an unused, empty ampule according to anembodiment of the invention;

FIG. 10 b is a pictorial view of the ampule shown in FIG. 10 a filledand ready to deliver an injection;

FIG. 10 c is a pictorial view of the ampule shown in FIG. 10 a in thedisabled state after an injection has been given;

FIG. 11 a is a perspective view of an alternate embodiment of afrangible piston for use in the ampule shown in FIGS. 10 a-10 c;

FIG. 11 b is an end view of the piston shown in FIG. 11 a;

FIG. 11 c is a view taken along the line A-A in FIG. 11 b;

FIG. 12 a is a pictorial view of a portion of the invention showingampules attached to a cardboard/paper strip;

FIG. 12 b is an enlargement of a portion of FIG. 12 a;

FIG. 13 a is a pictorial view of the ampule strip shown in FIG. 12 awhen inserted in an unfolded magazine;

FIG. 13 b is an enlargement of a portion of FIG. 13 a showing a close-upview of posts for securing ampule strips to a folding magazine;

FIG. 13 c is a pictorial view of the apparatus shown in FIG. 13 a with aset of magazine wings being folded over the center segment;

FIG. 13 d is a pictorial view of the apparatus of FIG. 13 a in afully-folded magazine ready for injection;

FIG. 14 a is a pictorial view of another embodiment of an aspect of theinvention showing an ampule strip coiled up and placed in a rotatingauto-feed magazine;

FIG. 14 b is a pictorial view of the embodiment shown in FIG. 14 a witha cover placed on the rotating auto-feed magazine shown in FIG. 14 a andready for use;

FIG. 14 c is a pictorial view of a negator spring used in the magazineshown in FIGS. 14 a-14 b, 16, 17 and 18 a-18 c.

FIGS. 14 d and 14 e are schematic drawings of a pawl and ratchet deviceused in the magazine shown in FIGS. 14 a, 14 b, 16, 17 and 18 a-18 c.

FIG. 15 is a pictorial view of ampules according to the inventionlocated in a tray or crate assembly;

FIG. 16 is a pictorial view of the second embodiment of the inventionshown in FIG. 2 retrieving a filled ampule from a rotating auto-feedmagazine as shown in FIGS. 14 a and 14 b;

FIG. 17 is a pictorial view of another embodiment of the magazineportion of the invention showing a linear auto-feed magazine with anopen cover;

FIG. 18 a is a pictorial view of another embodiment of the magazineaspect of the invention showing a rotatable auto-feed magazine with animproved structure for ampule retrieval;

FIGS. 18 b and 18 c are views of the magazine shown in FIG. 18 a in twomounting modes.

FIG. 19 is a pictorial view of a filling station according to theinvention in partially exploded form;

FIG. 20 a is a schematic view of an ampule according to the inventionwith a lyophilized/diluent vaccine separated by a mixing piston with aone-way valve;

FIG. 20 b is a schematic view of the ampule shown in FIG. 20 a withinternal lyophilized vaccine and external mixing diluent being forcedinto the exit nozzle;

FIG. 20 c is a schematic view of an ampule according to the inventionwith lyophilized vaccine, having an external appendage containing themixing diluent;

FIG. 20 d is a schematic view of the ampule shown in FIG. 20 c having anexternal appendage containing both lyophilized vaccine and diluentseparated by a barrier;

FIG. 20 e is a schematic view of another aspect of the invention showinga magazine full of ampules, each with a collapsible storage unit; and

FIG. 20 f is a schematic view of another variation of an ampuleaccording to the invention showing it with lyophilized vaccine anddiluent separated by a slidable frangible barrier.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 illustrates a customized, all-inclusive, carrying case 12 for theportable injection system, station or kit 10 according to an embodimentof the invention. Each carrying case 12 of the portable system 10contains all components necessary for a healthcare team to efficientlyadminister thousands of injections at the rate of up to 600 people perhour, this equipment to include several magazines, at least onehandpiece, enough battery power for the number of injections expected,manual arming means if needed, at least one filling system, severalbattery charging options and simple tools to effect repairs to thesystem components.

The case has retractable legs (not shown) for standing the unit in anupright position and flat panels from the four sides that can be pulledout to form a working surface (not shown) for the healthcare team if noother surfaces are available or convenient. Sterile components such asgauze, cotton balls, band-aids, etc., will also be housed in the case.Several ampule strips should be included in the case as a fill-in orbackup in case a delay occurs in the normal procedure for delivery;however, for the enormous number of inoculations needed for a massimmunization campaign, it is anticipated that the required number ofampules will be transported to the site in separate cartons and/orshipping magazines, and might even contain pre-filled liquid orlyophilized ampules.

One of the main embodiments of the invention is referred to as a“Motor-Off-Tool” or “MOT,” where the electrically operated motor(discussed below) is separable from the injection device that it isdriving. The injection device preferably includes a handpiece foreffecting injections.

FIGS. 2 through 4 are illustrations of the various ways to deal witharming a Motor-Off-Tool (MOT) device, i.e., it includes a handpiece 14containing an injection spring (discussed below) and a trigger 16, but amotor 15 and a battery 17 are on motor-battery belt assembly 18 arelocated off of handpiece 14. Because of this, MOT handpiece 14 is lessexpensive and extremely light at an estimated weight of approximately8.5 ounces (240 g), where the handpiece is made from an appropriateplastic, and the plastic and injection spring comprising nearly all ofthe weight of the handpiece. The reduced weight has the added advantageof less fatigue to the healthcare worker when thousands of injectionsare given.

FIG. 2 shows a Motor-Off-Tool apparatus 100 having a belt-motor assemblylocated on a belt pack 22, arm pack or the like, and is attachable to aconvenient location on the healthcare worker giving the injections. Amoveable center (not visible but similar to a speedometer cable) locatedinside tether or cable 26 is fastened on one end to a draw rod(discussed below) on handpiece 14, and is used for applying the pullingforce needed to compress an injection spring in handpiece 14, alsodiscussed below. The outside shell of tether 26 is connected tohandpiece 14 with a coupler mechanism 24. The other end of the movablecenter of cable 26 is attached to a motor drive 19 located on belt back22, and this end of tether or cable 26 is attached to the housing ofmotor drive 19 with a coupler or connection mechanism 28. After aninjection is given, a signal goes back from the handpiece to the motorcontrol which will instruct the motor to pull on the movable center ofcable 26 to again compress the spring in preparation for the nextinjection as explained later. The injection fluid or injectate is heldin disposable ampules 21. This option allows the vaccinator to movearound freely and provides for very high-speed operation, all the whilerequiring very little outside assistance. Mechanical tether 26 should beof adequate strength, and could be fairly stiff which, for somesituations will also possibly add unwieldy weight to handpiece 14.

FIG. 3 illustrates a manually operated foot pedal assembly 30 foractivating the movable center of mechanical tether 32 which functionsexactly as described for tether 26 in FIG. 2 for compressing the springin handpiece 14. The outer shell of tether 32 is connectable tohandpiece 14 with coupler mechanism 34. No additional energy is neededand no motor is involved for using this foot-operated device.

FIG. 4 shows a pair of Motor-Off-Tool (MOT) injectors residing inrearming station 40; however, in this case an electrically operatedarming station 42 is used. While not mandatory, the primary objective ofarming station 42 is for the vaccinator and an assistant to worktogether, wherein the vaccinator will give the shots and the assistantwill move the handpieces around as described below. Arming station 42has a pick-up cradle 44 for holding a fully armed Motor-Off-Toolinjector, and a rearming dock or port location 50 to accept an unarmedinjector. Arming station 42 can be adapted to hold more than one MOThandpiece, wherein two are shown in FIG. 4 as configured for use with anassistant. Cradle 44 on arming station 42 is for holding an injector 14that has already been armed and ready for use. A pick-up cradleadjustment knob 46 on arming station 42 is adjustable in order to placethe handpiece at an angle that is most convenient and comfortable toprovide access to a fully armed injector 14 for the vaccinator. Armingstation 42 also has an arming station base 48 on which theaforementioned pick-up cradle 44 and a rearming dock or cradle 50 islocated. In addition, base 48 also has an optional or back-up manualarming lever 52 to rearm the handpiece resting in dock or cradle 50 inthe event electrical power is not available, all of which are discussedbelow. At the beginning of an immunization sequence, both injectors aretypically unarmed. When arming cradle 50 senses the presence ofhandpiece 14, it pulls the injector draw rod to compress the injectionspring to the latched position, as discussed hereinafter. After armingis completed, the armed handpiece is moved to pick-up cradle 44, and thesecond injector is placed in arming cradle 50 and armed. At this point,the vaccinator takes an armed injector from cradle 44 to give aninjection and the assistant will move the second injector to pick-upcradle 44 while at the same time the vaccinator will squeeze trigger 16of handpiece 14 to then release the injection spring, therein driving aram in handpiece 14 to expel the jet velocity fluid from the ampule.After giving an injection, the vaccinator ejects used ampule 21 anddeposits handpiece 14 into the now empty rearming cradle or dock 50, andpicks up the armed handpiece 14 from cradle 44 wherein handpiece 14 isready to retrieve a new ampule 21 for the next injection. Benefits witharming station 40 include the elimination of any kind of tether, so thatthe vaccinator's arm has complete freedom of movement. Also, in acampaign with an adequate supply of assisting personnel, which is oftenthe case in mass campaigns, arming station 40 will relieve thevaccinator from all duties except for delivering injections, thusinsuring an efficient, high-speed operation. If, however, a vaccinatoris working with very little assistance, the arming station 40 optionwould require more motion and effort on the part of the vaccinator thanthe mechanical tether option. Also, unlike the mechanical tether option,in which the vaccinator can move around freely, this option requires thevaccinator to remain close to the arming station in order to swaphandpieces 14 after each injection. The arming station concept is alsoconveniently applied to the personal use injector, wherein the motor andbattery can be housed in a unit that also serves as a compact storageand carrying case that is easily concealed by the user, and which alsomakes the handpiece very compact, lightweight and easily maneuvered fora personal injection.

A second main embodiment of the invention is referred to as a“Motor-In-Tool” or “MIT,” where an electric motor is plugged into orotherwise is a part of the injection device which it is driving, in thiscase a handpiece as described below. Referring to FIGS. 5 a-5 c, theyshow together a Motor-In-Tool device or apparatus 200 having a handpiece114, and in the embodiment of FIG. 5 b, a battery-belt assembly 118having a battery 120, and a motor module with a motor 119.

FIGS. 5 a-5 c illustrate various options for arming the Motor-In-Tool(MIT) injector or handpiece 114. Depending on the required shotcapacity, battery 120 can be housed on handpiece 114 or in a separateoff-tool compartment as shown in FIG. 5 b. Just like the Motor-Off-Tool(MOT) handpiece 14, the MIT handpiece 114 houses an injection spring,the force transfer system that includes a plunger rod such as ampuleplunger rod 403 as illustrated in FIGS. 8 a-8 c, trigger, and the ampulegrip/release system as discussed in greater detail below. Thus, withreference to FIGS. 10 a-10 c, ampule 21 includes an injecting piston718. Piston 718 is driven forward by plunger rod 403 to force injectablematerial into the intended target.

FIG. 5 a illustrates a removable module 130 containing a geared downmotor 132. Depending on the desired injection pressure and stroke lengthfor a particular injector design, any number of conversion values couldbe used, one value implemented for this system has an armature speed ashigh as 13,900 revolutions per minute (RPM), but with very low torque.This high armature speed is reduced by 29:1 with an appropriate gearreduction to yield an output speed of 480 RPM to shaft 136 (8revolutions per second), and except for an inevitable loss due toconversion efficiency, the torque output is therefore increased by thesame ratio, thus providing the power needed to compress the injectionspring (not shown in this figure). In this embodiment, a battery 134 isconnected to the motor inside of module 130, wherein both the motor andbattery are connected to the handpiece 114 during its operation byinsertion of an output shaft 136 into a mating receptacle 138 onhandpiece 114.

FIG. 5 b illustrates a removable module that contains only the geareddown motor 119 when the motor is connected to handpiece 114, but battery118 is off the tool during operation and is connected to motor 119 withan electrical tether 140. Motor 119 has the same type motor shaft 136 asshown in FIG. 5 a for insertion into receptacle 138. This is a morelikely situation for providing power to handpiece 114 when thousands ofinjections are expected, i.e., a larger remote battery pack can beclipped onto a belt or vest, carried in a pocket, or placed on astationary surface next to the vaccinator without the risk of excessivefatigue from constantly moving the greater weight. The MIT handpiece 114(that is, when motor 119 is connected thereto) is estimated to weighabout 14 ounces and is somewhat larger than an MOT handpiece 114 (whenmotor 119 is not connected); however, it is still much lighter than anyother mass campaign injector known to the inventors. The MIT handpiece114 weighs about 14.5 to 16.5 ounces, wherein added to the 8.5-ounce MOThandpiece 114 are motor 119 at about 4 ounces and the linkage from themotor to the gears weighing from 2 to 4 ounces. The option shown in FIG.5 b provides the vaccinator full range of arm motion and completefreedom to walk around; that is, handpiece 114 does not have to be putdown between injections and one-handed operation to load, inject, andeject ampules 21 is possible. While not shown, it is clear than othersources of power, such as solar or main power, when converted to thevoltage needed can also be used to drive the motors in FIG. 5 b.

FIG. 5 c shows a module 142 for the manual arming of handpiece 114, andwhich is connected to the injector in the same manner as that describedfor the modules of FIGS. 5 a and 5 b. This format takes the place of themotor and the battery pack needed to energize it. Module 142 has ahousing 144, and a manually driven handle 148 coupled to geared downinterface prior to moving output shaft 146 which is connected toreceptacle 138 on handpiece 114 during its operation. Manual arming ofhandpiece 114 is facilitated by rotating handle 148 several times toprovoke the amount of rotation needed on output shaft 146 to compressthe injection spring. While not shown in any of the figures, the MITinjector 200 can also be manually rearmed by compressing the spring fromthe front end when the injector nose is inserted into a correspondingmanual rearming station.

FIGS. 6 a and 6 b show one version of a complete MIT injector 114′, andFIG. 6 b is a cut-away view of the motor location and the othersignificant components. In this case, motor 119′ receives power fromelectrical tether 140 as illustrated in FIG. 5 b, but in this case,motor 119′ is a permanent fixture on injector 114′. This figure alsoincludes an ampule grip/release system, force transfer system, trigger,and the injection spring, all which are also incorporated in the MOTdesign 100. Ampule 21 is not installed in handpiece 114′ in thesefigures.

With reference to FIG. 6 a, handpiece 114′ has a housing 150 with atrigger 116′. Turning to FIG. 6 b, an injection spring 152 is shown inthe compressed state and is held in compression between a ball screw nut154 and an injection release sleeve 156 having a shoulder 158 againstwhich spring 152 rests, wherein, motor 119′ rotates ball screw nut 154in the spring compression direction until it reaches and actuates amotor stop switch which is more fully explained with the embodiment ofFIG. 7. Optionally, the spring can be made to latch in this position andthe motor is instructed to immediately return ball screw nut 154 to thelower portion of screw 164. Alternatively, ball screw 154 can stay inthe position shown until the injection is given and the used ampulereleased from the handpiece, at which time, the motor will reverse theball screw position as described to be reset to again compress spring152. Both techniques have been implemented, the advantage of immediatereversal is saving time in preparation for the next injection. A forcetransfer system 160 transfers force from injection spring 152 to system160 and ultimately to a ram for driving a piston inside an ampule. Motor119′ is mounted in housing 150 and has a drive shaft 161 for rotating aspur gear 163, which in turn rotates a spur gear 162 to rotate a ballscrew 164 which moves ball screw nut 154 to compress injection spring152. No thrust bearing is required for protecting drive shaft 161because the load is decoupled from the motor and the gearbox by virtueof the offset nature of the spur gears. An electric tether connectorport 166 is shown as a connection for connecting a battery or, assuggested for the FIG. 5 embodiments, connecting other sources ofelectrical power to motor 119′.

Force transfer system 160 includes a casing 168 for holding an ampuleplunger rod, a transfer mechanism held in casing 168, and a ramrodextending from injection release sleeve 156 to effect the activeoperation of the transfer mechanism. The ampules are held in handpiece114′ by gripper jaws 172, the operation of which is discussed in furtherdetail for FIG. 8 c below. The foregoing mechanism included in handpiece114′, with the exception of motor 119′ installed in handpiece 114′, isessentially the same as for the MOT handpiece 14.

When trigger 16, 116 or 116′ is squeezed on any of handpiece 14, 114,114′, the stored energy in injection spring 152 exerts the appropriateforce on transfer system 160 (more fully described below for FIG. 8 a),which then applies injection pressure to an ampule ramrod (discussedbelow). After an injection, an ampule release button 170 is compressedand the ampule capture sleeve (discussed below) is pulled back from itslocked position. The gripper jaws 172 expands, are held open, and theused ampule 21 either falls out or is pushed away from the front end ofhandpiece 114′. There is no need for physical contact by the user;however, if desired, ampule 21 can be inserted and extracted manually.As described above, at some point in the cycle, motor 119′ reverses itsdirection to reset handpiece 114′. To install a new ampule 21, the frontend of the handpiece 114′ is placed over the mating back section of anew ampule 21, and the capture sleeve is returned to the locked positionas soon as gripper jaws 172 are released and closed. The ampule is nowsecurely held in place for the next injection. Apparatus is provided forpreventing the actuation of a ramrod for normally injecting injectatefrom an ampule unless gripper jaws 172 are properly holding an ampulebecause the actuation of the ramrod without a properly held ampule couldpose a dangerous situation since the ramrod could provide a dangerousimpact if it were to strike a person.

FIGS. 7 a, 7 b, 7 c and 7 d show the internal structure for oneembodiment of the MIT injector 200. Injector 200 has a handpiece 114″shown in FIGS. 7 a and 7 b in the armed position, and FIGS. 7 c and 7 d,the same in the fired or unarmed position. MIT handpiece 114″ includes ahousing 150′ having a ball screw assembly 172, which includes a motorand gear train 119″, a coupler mechanism 174, a ball screw 164′ and aball nut 154′. Coupler mechanism 174 represents a fixed point whichlocks the motor in the housing while at the same time coupling motor119″ and its gear box (included in the motor or housing) to ball screw164′. Member 174 is able to pivot very slightly (a few degrees) to allowfor movement of ball screw 164′ and a power linkage 176 as ball screwnut 154′ moves up and down on ball screw 164′ during the arming process.Coupler mechanism 174 also includes a thrust bearing (not detailed inthe figure) to protect the motor and gear train from the in-line springload. Power linkage 176, described in more detail below, operativelyattaches to ball screw assembly 175 with an appropriate connector orpivot point 192. The injector spring is included in a rear or right partof a spring tube assembly 178. A battery 118′ is located within housing150′ above spring tube assembly 178. An ampule capture sleeve 180 holdsan ampule 21. The discharge or removal of a used ampule 21 isaccomplished by the sidewise movement of an ampule release trigger 182.A ready indicator 184 is located at the rear of headpiece 114″ andextends out the rear end of injector 200 as shown when the injectionspring is compressed. A front view of the unit is shown in FIG. 7 b.

Power linkage 176 includes a first link 186 connected to ball screw nut154′ by connector 192 about which first link 186 can pivot. Link 186 hasa free end 188 with a longitudinal slot 190. A second link 194 isconnected to a pin or pivot pin 196 extending from trigger 116″. Secondlink 194 can pivot about pin 196. A third link 198 is pivotally mountedon a pivot pin 201 carried on a tube housing 202 which allows pivot 201to slide to the left when the injection spring is released, and a fourthlink 204 is mounted at one end to a pivot pin 206 fixed on handpiece114″, and at its other end to a connecting pin 208 extending throughslot 190 in first link 186. Link 198 is connected to fourth link 204 bymeans of the same connecting pin 208 for second link 194. Pin 208 isheld in place by a retainer 210.

As mentioned, FIG. 7 a shows MIT handpiece 114″ in a loaded or armedposition. When trigger 116″ is actuated, injection release or secondlink 194 is forced upwardly by trigger 116″, therein, connecting pin 208is raised above the center point of links 198 and 204 to unlock theselinks, and the compression spring in spring tube assembly 178 isreleased and rapidly moves to the left, driving an ampule plunger rod orramrod into ampule 21 to cause the discharge of the injectate heldtherein. Connecting pin 208 moves to the upper end of slot 190 in firstlink 186, and then, in this embodiment (other motions are possible),upon the sidewise actuation of ampule release trigger 182, anampule-eject spring engages an ampule ejector sleeve which bothwithdraws jaw capture sleeve 180 to release jaw expansion springs (notshown in this figure) from holding ampule 21 in place in handpiece 114″,and a plunger return and ampule-eject spring drives an ejector sleeveagainst ampule 21 to either eject or to allow ampule 21 to fall awayfrom the open gripper jaws (discussed in detail with respect to FIG. 8c). The condition of handpiece 114″ after firing, i.e. after aninjection has been made and just prior to ejection of ampule 21 from thegripping jaws 172, is shown in FIG. 7 c.

Ampule release 182 can also release an ampule in the event no injectionis made. It also effects release of an ampule if the main systemmalfunctions.

It is noted that the fully compressed spring in this embodiment latcheswith a slightly over-center toggle composed of third link 198 and fourthlink 204; therefore, spring release is easily facilitated with a smallforce to the center point of this toggle arrangement when trigger 116″is actuated. Ball nut 154′, screw 164′ and motor drive 119″, move inboth the forward and reverse directions by virtue of electrical switchactuation as described below. As described earlier, a ready button 184extending from the rear end of housing 150′ tells the user when injector114″ is fully armed for an injection.

After an injection has been accomplished and injector 200 moves from thecondition in FIG. 7 a to that of condition 7 c, the direction ofrotation of the shaft of motor 119″ is reversed. Control of motor 119″is facilitated with the use of switches 214, 216, and 218. When trigger116″ is actuated and toggle 204/198 is released to facilitate theinjection, trigger 116″ also causes a switch arm 212 to move upward witha guide and stop member 220 riding along a slot 213, thereby releasingswitch 216. The release of switch 216 enables motor 119″, but this alonewill not permit it to operate. At this point, there are two possibleembodiments for having the motor rearm the injector. In the firstembodiment, when ampule release trigger 182 is actuated and the usedampule falls away from the injector, switch 218 is released, and thecombination of switch 216 and 218 enable motor 119″ to rearm theinjector 200, at which time, ball nut 154′ moves in the downwarddirection along screw 164″. When nut 154″ reaches the bottom of ballscrew 164′, arm 212 slides downward with guide and stop member 220riding along slot 213, and switch 216 is again compressed, while at thesame time, toggle 204/198 latches to its slightly over center position.Re-compression of switch 216 when ball screw 154′ reaches the bottomcauses motor 119″ to reverse direction and ball 154′ immediately returnsto the upward part of screw 164 as shown in FIG. 7 a. When ball screw154′ reaches the top, it pulls on shaft 215 which in turn produces aslight pull on coupler 174 to pull coupler 174 away from switch 214, andthe motor stops. In an alternative embodiment for rearming the injector,motor 119″ reversed direction as soon as the injection is completed.This saves time between shots, however, it also provides the risk of dryfiring the injector if the trigger is pulled before a new, filled ampuleis inserted into the injector. The choice between the two embodiments isdetermined by the conditions where the injector is to be used.

It should be noted that the manual backup, i.e., for situations whereelectrical power is unavailable, could be just as fast as automaticarming, but fatigue to the user could be much greater due to thephysical energy needed at the rapid rate expected. Whatever the case,the manual feature is necessary to assure that all injections arecompleted at the location before the healthcare team moves on.

FIGS. 8 a-8 c illustrate the details of a complete Motor-Off-Toolinjector 400; however, the inner workings, with the exception of how itis armed, apply to the Motor-In-Tool injector as well.

The FIG. 8 a cut-away shows the off-axis energy transfer systemconsisting of a series of balls in a tube and all of the other elementsdescribed above. The off-axis transfer of power was developed in orderto provide a handpiece that was less threatening to children than thegun type structure that has typically been used. This model is alsoeasier to handle than the straight-line version (similar in shape to aconventional flashlight), provides for a better distribution of weight,and helps reduce the onset of fatigue to the healthcare worker. Severalmethods were reduced to practice, each having its own advantages anddisadvantages for certain situations in mass immunization.

Referring to FIG. 8 a, MOT 400 includes a handpiece 414 having a housing450 with a trigger 416, and a force transfer system 402 having ampuleplunger rod or ramrod 403, force transfer balls 405 and a ramrod 407.Force transfer balls 405 are held in and tangential to the insidesurface of curved housing 409. Handpiece 414 further includes a draw rod411, a spring tube 413 housing an injection spring 415 and a springretainer nut 417. An injection release sleeve 456 includes part ofcurved housing 409 with force transfer balls 405, as well as six releaseballs 419 which can be transferred from an annular channel 421 to anannular pocket 423. Handpiece 414 has an ampule release button 425 andleaf springs 427. Ampule release from the front end jaw structure isessentially the same as that described for FIG. 8 c below.

FIG. 8 b is a blown-up view of force transfer balls 405 shown in FIG. 5a. Balls 405 are preferably made from steel, and there are “hat” members429 inserted between each of the balls that are intended to improve theefficiency of this transfer by helping maintain alignment of the ballsto reduce wall friction. Hat members 429 are preferably made fromDelrin. While not shown in the figures, tube 409 can also contain ahydraulic fluid with sealing pistons at either end, rather than balls405. The fluid, along with these pistons, will transfer the power toampule plunger rod 403 when the injection spring 415 is released.Tubular transfer system 402 is the most compact and lightest weight ofthose disclosed; however, its efficiency is not as great as some of theothers; for example, while somewhat larger, a chain or cable connectedto a pulley and gear motor combination can also provide the springcompression at higher efficiency. Selection of a particular transfersystem will depend on the energy available to accommodate an acceptableefficiency, as well as the premium placed on weight and size of thedevice.

FIG. 8 c is a blown up view of the circular jaw structure shown in FIG.8 a. As pointed out earlier and discussed below, these jaws allow for ano-personal contact procedure when grasping and discarding an ampule,and because of that, they also have important utility for personal useinjectors when used by healthcare workers for a particular patient whomight be harboring dangerous blood born pathogens, thus eliminating therisk of cross infection to the worker.

In FIG. 8 c, an ampule 21 is held in handpiece 414 by three gripper jaws472. Ampule 21 has a housing 700 with a cylindrical forward outersurface 702 and a tapered rearward surface 704 that is narrow at itsfree end and thickens until it reaches a peak 706 after which it tapersinwardly towards the longitudinal axis of ampule 21 to form a slantingshoulder 708. Gripper jaws 472 each have a head 475 with an inclinedampule engaging surface 476 for engaging ampule shoulder 708. Jaws 472are biased outwardly by jaw expansion springs 478. A jaw capture sleeve480 engages an abutment 482 on the outside of head 475 of jaws 472 tohold jaws 472 in a closed position against the bias of springs 478.Ramrod 403 follows the longitudinal axis of jaws 472 and ampule 21 (ifinstalled), and as explained earlier, effects the ejection of serum orother injectate from ampule 21. A guide and holder 484 has a forward endportion with an inclined inner surface 486 for engaging and holdinginclined rearward surface 704 of ampule 21, an inward collar 488 and arearward cylindrical portion 490. An ejector sleeve 492 extendspartially along ramrod 403, and the inner surface of collar 488 ofrearward portion 490 engages sleeve 492 and holds it against ramrod 403.A plunger return and ampule spring 494 extends partially along ramrod403, including a forward portion between ejector sleeve 492 and ramrod403.

A jaw capture sleeve return spring 496 extends along the inside surfaceof the rear part 497 of jaw capture sleeve 480, and has a forward endabutting an inwardly extending collar 498 of sleeve 480 and a rear endabutting a gasket 500 extending between the rearward end of sleeve 480and the rearward portion 490 of guide and holder 484. A retaining ring502 is located in an annular groove 504 of guide and holder 484 formaintaining gasket 500 and sleeve and return spring 496 in place.

FIG. 8 a shows the MOT injector 400 in its loaded or armed condition,ready for giving an injection. The user actuates trigger 416 by causingit to pivot on an annular axle (hidden in this figure but located closeto the left end centerline of plunger rod 403), which causes a cam 506on trigger 416 to engage inclined surface 508 to force injection releasesleeve 456 downwardly along tube 409 containing balls 405. This causesinjection release balls 419 to move from annular channel 421 intoannular pocket 423 in injection release sleeve 456. Balls 419, which hadbeen restricting the release of injection spring 415 in spring tube 413,now permit the release of spring 415. Therein, injection spring 415,which at its upper end engages a drive member 510, in turn drives drawrod 411 into ramrod 407 to apply the force from spring 415 into forcetransfer balls 405 to move upwardly, the forward ones of which movingaround the curve in the upper end of tube 409, to drive ampule rod 403into the inner end of ampule 21 of such force as to cause the ejectionof injectate under jet pressure through its discharge port 710.

It is noted that ampule 21 in this embodiment is shown with an exit portperforator 460 covered by a collapsible protective front end 462 whoseinterior contains a springy or resilient return material. When front end462 is pressed against an injection site, it collapses under the appliedforce to then expose perforator 460 through the narrow access hole atthe front. The perforator now enters the very outer layer of the bodyand the injection is thereafter delivered. When the injection iscompleted, protective cover 462 re-expands to again cover perforator 460thus avoiding the risk of injury to the user. Importantly, protectivefront end 462 is manufactured with a side-wise bias that breaks losewhen the perforator is first exposed, consequently, when perforator 460is drawn back into protective front end 462, the narrow exit hole in 462will shift to the side as shown in FIG. 8 d, therefore making itimpossible to again expose perforator 460. This feature providesprotection against any form of after shot “stick” or reuse by preventingthe perforator from again becoming exposed, and will, in fact, destroythe perforator is such front end compression is again applied.

Thereafter, the actuation of ampule release button 425 withdraws jawcapture sleeve 480 to the left as shown in FIG. 8 c, away from forwardend 702 of ampule 21. This results in jaw expansion spring 478 rotatinggripper jaws away from ampule 21 so that ampule-engaging surface 476disengages ampule shoulder 708. Plunger return and ampule-eject spring494 urges ejection sleeve 492 forwardly against the rear face 712 ofampule 21 to eject ampule 21 from MOT handpiece 414.

Since this embodiment is that of a motor-off-tool (MOT) injector,withdrawal of ramrod 407 from the forward or fired position must firstbe facilitated before a new ampule can be inserted into gripper jaws472. Thus, injector 414 is inserted into either a motor driven armingstation or a manually driven arming station to grab hold of draw rod 411and pull on it to recompress spring 415 to the injection ready position.A new ampule 21 can now be inserted in the forward end 485 of guide andholder 484, and jaw heads 475 will ride along inclined surface 704 ofampule 21 until peak 706 rides over the gripping portion of jaw head 475to releasably lock ampule 21 in place. Jaw capture sleeve return spring496 then moves jaw capture sleeve 480 to the right as shown in FIG. 8 c,to move gripper jaws 472 to the closed position.

MOT handpiece 414 is now ready for the next injection. The entire systemin this and other embodiments have been found to make 600 injections perhour, including the injection of injectate from each ampule, discardingthe ampule and reloading a new ampule.

FIG. 9 illustrates a full external view of the FIG. 7 a-7 c MIT injector200 as seen when ejecting a used ampule 21 into a trash container Twithout the need for any physical contact by the user.

FIGS. 10 a-10 c are three views of one version of a self-destruct ampulethat is conveniently used with this injection system.

FIG. 10 a shows ampule 21 prior to filling. In order to maintainconsistency as to the location of the proximal and distal ends of theampule for the discussions to follow, the proximal end is always thatend which is closest to the injector, i.e., the part of the ampule thatis held by the grasping jaws described earlier. Each ampule 21 includesits thin plastic shell or housing 700, cylindrical forward outer surface702, tapered rearward surface 704, peak 706, shoulder 708, an orifice ordischarge port 710 and rear face or proximal end 717. A channel or bore714 forms a chamber 715 extending along the longitudinal axis of ampule21, and is open at the rearward or proximal end 717 of ampule 21.Orifice 710 is located at the forward or distal end 716. Injectionpiston 718 is located at the distal end 716 while a spool 720 and alocking spring assembly 722 remain at proximal end 717. Piston 718 ismade from an appropriate plastic and has a head portion 724, a body 726and a base 728. Spool 720 has a head 730, a body 732 and a base 734.Locking spring 722 is wrapped around body 732 of spool 720, and has leafspring members or fingers 736 which are biased outwardly from thelongitudinal axis of ampule 21 towards the side wall 714 of chamber 715.The leaf members 736 of the locking spring 722 apply slight outwardpressure to the inner diameter (ID) of bore 714, thus enabling lockingspring assembly 722 to maintain position within bore 714. Herein liesanother feature that, in some cases, would find use with a personal useinjector. However, it should be noted that in some cases where dangerouspathogens are not an issue, some personal use injectors actually promotethe reuse of ampules to facilitate greater economy to the user.

FIG. 10 b shows a filled ampule. The distal end 716 of ampule 21 isinstalled into the filling station (shown in greater detail in FIG. 19),and pressurized injectate is forced into chamber 714 through the orifice710, thus driving piston 718 towards spool assembly 720 at proximal end717 of ampule 21, wherein it makes physical contact with spool 720 andlocking spring 722 and comes to a stop. Due to outward pointing fingers736 of locking spring 722, assembly 722 is unable to move any further inthe proximal direction. The concept of filling through the exit portwith the application of pressure to the vaccine reservoir offers asubstantial advantage by avoiding the insertion of air into theinjectate chamber during the filling process. This as opposed to themore common practice of creating a vacuum in the injectate chamber whenthe plunger is pulled back. While the pulling procedure certainly drawsfluid into the injectate chamber, it also draws air in at the same time,therein requiring an extra step of carefully pushing the plunger forwarduntil all of the air is expelled before giving the shot.

FIG. 10 c depicts an ampule-21 after the injection is completed. Plungerrod 403 makes contact with end or base 734 of spool 720, thus drivingthe spool 720, locking spring assembly 722 and piston 718 forward athigh speed to force the high velocity injectate out through orifice 710as a coherent jet stream. Once the injection is complete, piston 718 isfirmly lodged in distal end 716 of ampule 21, making reuse virtuallyimpossible to further reduce the likelihood of cross infection.

FIGS. 11 a-11 c depict an alternate embodiment of the piston used inampule 21 that avoids the use of a locking spring to disable the ampule,but relies instead on a very thin frangible section just behind anO-ring seal on the piston. After the piston reaches the end of theinjection stroke and strikes the distal end of the ampule, the injectorram continues in the forward direction just far enough to produce anadditional compression force on the piston which provokes a separation,or breakage, of the piston at the frangible ring. Once the piston isbroken into two parts, reuse of the ampule is impossible. In anotherform of the same idea, the injector ram fractures a frangible centersection on the piston. After the piston has fully pushed forward tocomplete the shot, a movable center rod will continue beyond the end ofthe ram and force a hole in the frangible member; therefore, if a usertries to refill the ampule, the remains of the piston cannot be moved tothe full position.

Thus, still referring to FIGS. 11 a and 11 b, an ampule piston 750 isshown. Piston 750 has a head 752, a body 753, and an annular groove 754separated by a pair of surfaces 756, 758 by a distance sufficient toengage in sealing contact an O-ring 760. An elongated, annular groove762 extends between a pair of collars 764, 766. A closed bore 768 (FIG.11 c) extends from an end 770 of piston 750 and ends in a conicalsurface 772. The narrow portion 774 between conical surface 772 andsurface 758 of groove 754 forms a frangible web area. As explainedabove, in use a ram such as ampule plunger rod 403—when activated—isdriven into the rear surface 770 of piston 750 as it moves through itsinjection stroke to eject injectate from an ampule such as ampule 21from chamber 715 through orifice 710. After ampule piston 750 reachesthe bottom of ampule 21, plunger rod 403 continues its forward motionuntil its compressive force breaks the frangible web area at narrowportion 774, rendering piston 750 useless and ampule 21 disabled againstreuse.

The item shown in FIGS. 12 a and 12 b is an example of ampules 21connected together on an ampule strip 800 comprising a cardboard andpaper combination, with tear-away paper strip 802 looping over each ofthe ampules as they rest on cardboard backing 804. Ampules 21 areaffixed to the cardboard backing when the paper overlay 802 is securedto the cardboard backing 804 by a suitable adhesive 806. Cardboardbacking 804 extends beyond distal face 716 of each ampule 21, protectingthe orifice 710 from incidental contact and possible contaminationduring handling. A loop belt 808 is configured and serpentined in such away as to form folds 810 to hold ampules 21 securely inside of eachother in the folded over strip during shipping, handling, and filling,but allows ampules 21 to be easily torn away when a shear load isapplied by the handpiece jaws (such as jaws 472) when pulling ampules 21out of ampule strip 800, i.e., a tear-away system. Ampules 21 in FIGS.12 a and 12 b are shown prior to insertion into the magazine system(described in more detail below). An alternate embodiment (not shown)has the ampules connected together during the molding process, butinsertion into the magazine and the tear, or breakaway feature isessentially the same.

Each ampule strip 800 preferably contains a number of 0.5 ml ampules 21.Reconstitution of a 50-dose cake of lyophilized vaccine with 30 ml ofdiluent typically yields more than 50 doses of vaccine, especially withthe highly efficient filling station described below. While a greaternumber is possible, the number of ampules in the strip will be equal tohalf the average number of doses of vaccine the filling station willextract from the vial (i.e. two ampule strips per vial of vaccine,wherein a strip will preferably hold between 26-28 ampules). As shown inFIGS. 12 a and 12 b, ampules 21 are spaced approximately 10 mm (0.400″)apart, allowing strip 800 to fold in half lengthwise (FIG. 12 a),nesting ampules 21 facing one another into the intervening spaces (FIG.12 b) for ease of shipping and filling.

The folded strip will be removed from its sterile pouch and interfaceddirectly with the filling station (as discussed below) advancingiteratively to allow the filling nozzle to access each ampule 21 andforce reconstituted vaccine through its orifice 710 described above forFIGS. 10 a-10 c. The vaccine will push ampule piston (such as piston 718or 750) back until it stops against a pre-installed spool (such as spool720) and lock ring (such as locking ring 722), insuring a precise amountof injectate in each ampule 21. This spool and lock ring will alsoprevent the piston from moving in the reverse direction once theinjection is completed, thus disabling the ampule and preventing reuse.Once the ampules 21 are filled, strip 800 is ready to go into coldstorage for use later in the day or to be installed directly into amagazine.

FIGS. 13 a-13 d and 14 a-14 b show two distinct, yet similar, off-toolampule management systems available with the injection station of FIG.1, and the handpiece designs described above. By virtue of the ampulestrip design in FIGS. 12 a-12 b, a greater number of ampules areavailable for the off-tool magazines than that described for the on-toolmagazines of prior art patent U.S. Pat. No. 5,318,522. Either of themagazines can be attached to a working surface, such as the injectionsystem carry case, a table, a lanyard around the user's neck, belt pack,arm pack or wrist mounting, and/or any other convenient location.

The magazine 820 shown in FIGS. 13 a-13 b is a folding magazine. Thissystem holds a set of ampules 21 in a fixed position relative to oneanother, and are removed from any location, one at a time by thehandpiece. This system comprises three plastic segments: a centersegment 822 and two winged sections 824, 826 hinged to each side.Segments 822, 824, 826 are initially unfolded, and the open magazine isplaced on a flat surface, allowing the ampule strip to be laid into theunfolded magazine (FIG. 13 a). Small posts 828 (FIG. 13 b) on the innersurface of magazine segments 822, 824, 826 press securely into a set ofmatching holes 832 in an ampule strip backing 830, properly locatingstrip backing 830 on the support walls 834, 836, 838 (FIG. 13 c) on eachof segments 822, 824, 826, and holding it in place. Additionally, anedge 840 of backing 830 closest to proximal end 717 of ampules 21 fitsfirmly against retaining rib 708 on the inside surface of magazinesegments 822, 824, 826, keeping strip backing 830 from sliding whileampules 21 are being extracted one at a time. Ampule strip 800 wheninserted in magazine 820 includes a loop belt 842 attached to stripbacking 830 by an appropriate means such as an adhesive. Loop belt 842and backing 830 are flexible so that they can bend with the folding ofmagazine 820. Loop belt 842 has a sequence of loops 844 being generallysemi-cylindrical for grasping ampules 21 around ampule body 702 to holdampules 21 in place. Retaining rib 708 extends across each of segments822, 824, 826 for engaging the edge of ampule strip 800 when it isinserted in the magazine. Segment 822 has two pairs of opposing hingearms 848, 849 for cooperating with hinge arms 850 on each of segments824, 826 for forming two pairs of hinges 852. Hinge arms 850 each have apin 854 for extending through a hole 856 in hinge arms 848, 849 tocomplete respective hinges 852. Segment 824 has an end plate 858 andsegment 826 has an end plate 860 with a handle 862 attached to it bysome appropriate means or to be integral therewith. Finally, thesegments 824, 826 are folded over center segment 822, left segment 824first (FIG. 13 c). The end of right segment 826 snaps fully over theopposite ends of the center segment 822 and left segment 824, holdingthe system securely closed in its folded position (FIG. 13 d). Snappingoccurs by virtue of opposing fingers 864 extending from hinge arms 850into opposing notches 866 in end plate 860. Strip backing 830 and loopbelt 842 have strategically positioned pleats or perforations 868, 870to allow the folding to occur easily. The folded magazine 820 (FIG. 13d) has a solid bottom surface because of foot flanges 872, 874, 878 oneach of segments 822, 824, 826, to protect ampule distal ends 716 andalso to provide a place for possibly securing magazine 820 to a surface,either through hook-and-loop strips (e.g. Velcro©) or features whichaffix to matching surfaces on the injection system carry case. Foldedmagazine 820 also has solid sides 880, 882, which allow for gripping themagazine with one hand while extracting the ampules with the handpiecejaws. The relative position of the ampules in the magazine allows accessto each ampule in turn. Proximal ends 717 of the remaining ampulesprovide some guidance to the nose of the handpiece, helping the userlocate the handpiece nose (such as gripper jaw heads 475) appropriatelyfor jaws (such as jaws 472) to grasp the targeted ampule. After the lastampule 21 has been extracted, magazine 820 can be unfolded, ampule stripbacking 830 removed and discarded, and a new strip backing 830 of filledampules 21 installed. The advantage of folding magazine 820 issimplicity. With few parts and few manipulations necessary to operate,this magazine design is likely to be robust and take minimal time toload and unload. Protection of the orifice or distal end 716 of ampule21 prevents the possibility of cross infection, but because proximalends 717 of ampules 21 are exposed, some effort must be made by the userto insure cleanliness.

FIGS. 14 a-14 b illustrate a rotating auto-feed magazine 890. Thissystem advances the ampule strip along a track, presenting each ampuleat a consistent location for extraction. As with folding magazine 820,this system 890 is ideal for placement on a table, attached to theinjection system case, or ideally, on the opposite wrist to the handused to hold the injector. If desired, auto-feed magazine 890 could alsobe worn as a neck lanyard by the vaccinator. This magazine 890 comprisesa load chamber 892 that holds the ampule strip (such as strip 800 ofFIG. 12 a) and a rotating take-up spool 898 that collects the emptystrip as the ampules are removed, and is similar in operation to thefilm advance system of a camera (FIG. 14 a). This embodiment includesfour primary components: a base 894, a cover 896 (FIG. 14 b), take-upspool 898, and a constant-force negator spring 900 (FIG. 14 c) locatedand attached to the inside of spool 898. Spring 900 is shown outside ofspool 898 with FIG. 14 c for clarity. Housing base 894 has a bottom wall902, side walls 904 and interior guide walls 906 for cooperating withthe inside surfaces of side walls 904 to guide strip backing 908 ofampule strips 909 through load chamber 892. Wall 906 is alsoappropriately curved at wall section 910 so that load chamber 892 canreceive take-up spool 898. Cover 896 has a rim 912 that is configured toslip over and slidingly engage the upper portion of side walls 904.Take-up spool 898 has a slot 914 for receiving a tab 916 and stripbacking 908, for holding tab 916 as take-up spool 898 rotates to drawampule strip 800 (or 900 in FIG. 14 a) along its path in magazine 890.Ampule strip 909 has ampules 21 secured to strip backing 908 by someappropriate means, such as disclosed with reference to FIGS. 13 a-13 d.

In preparation for inserting ampule strip 909 into magazine 890, theuser pulls the wind-up cord (not shown, but see FIG. 17 for anequivalent one) which turns take-up spool 898 through severalrevolutions (counterclockwise in this figure) to turn spring 900 to thefully wound and latched position. A ratchet-type arrangement having apawl 918 and a ratchet groove 929 will prevent the cord from beingpulled back into the housing by wound up spring 900 because of thevertical left side on groove 929 and mating spring loaded pawl 918 onthe interior of magazine 890, however, the slanted surface on the rightside of groove 929 will allow spool 898 to rotate in the counterclockwise direction during wind-up by having spring loaded member 918slide over the slanted surface during each revolution. To facilitateloading magazine 890, ampule strip 800 is rolled into a coil and placedin load chamber 892 (FIG. 14 a). The user then threads an extended tailor tab 916 of strip backing 908 along the track or path as describedabove, affixing it to rotatable take-up spool 898. When cover 896 isplaced on to housing base 894, an appendage on the inside of cover 896(not shown) extends downward to interface with the surface of springloaded pawl 918 and push it out of the way to release take up spool 898.Application of spring tension from constant force spring 900 located inhousing base 894 draws strip backing 908 onto spool 898 until an ampule21 comes to rest against a stop position defined by wall portion 926.Cover 896, which can optionally be attached to the housing base by ahinge on housing base 894, is then placed over base 894 to protect theampules against contamination (FIG. 14 b). As stated above, the ratchetis released when pawl 918 is pushed out of mating groove 929 in theclosing of cover 896. This should be made clear by considering FIGS. 14d and 14 e. In order to cock or set spring 900 prior to the loading of astrip of ampules, a pull cord is pulled to rotate spool 898counterclockwise. As spool 898 is wound counterclockwise as shown inFIG. 14 a, spring loaded pawl 918 slides into groove 929 but does notstop the rotation due to the sliding of the inclined surfaces of pawl918 and groove 929 passing over each other. However, once a strip ofampules is inserted in load chamber 892, spring 890 would be free tounwind spool 898. This cannot occur, however, since while spring 900could unwind, spool 898 moves a small amount due to pawl 918 movingbelow spool 898 as shown in FIG. 14 e. Nevertheless, while pawl 918moves into groove 929 as shown in FIG. 14 d, the ampule strip is lockedin place. When cover 896 is closed, a bar 897 moves pawl 918 downward sothat it cannot stop the clockwise rotation of spool 898 as ampules areadvanced through magazine 890. This action-reaction will free spring 900and advance ampules 21 on backing strip 908 as described.

A funnel-like opening 930 in cover 896 provides access to the ampule 21resting against the stop defined by wall portion 926. The funnel featureallows the nose (the head of the gripping jaws) of the handpiece to beguided easily into position to grasp the ampule flange, i.e. the portionnear proximal end 717. Once an ampule 21 is extracted, spring 900 turnsspool 898 and automatically brings the next ampule 21 into position ataccess opening 930. After the last ampule 21 has been extracted, cover896 is removed so that ampule strip 909 can be removed and discarded. Anew ampule strip 909 is then installed as described above. Position ofthe pull-cord at all times is an indicator of the number of ampulesremaining in magazine 890 as the cord is stepwise pulled into thehousing when ampules 21 are extracted. Auto-feed magazine 890 makes useof the handpiece easier, because the ampule access point (opening 930)is always at the same place and the funnel in the cover (e.g. conical)can guide the jaws into position. To allow for the unlikely case ofmagazine malfunction, a slot 932 in housing side wall 904 provides amanual feed option where the user can pull the strip to advance the nextampule 21 into position for retrieval by the handpiece.

FIG. 15 illustrates the ampules housed in a crate assembly rather thanthe magazine structure described above. Accordingly, a crate 940 isprovided which is made of cardboard, plastic or other appropriatematerial, which has a series of orifices 942 defining the entrance toreceptacles 944 for receiving distal ends 716 of ampules 21 withproximal ends 717 extending from receptacles 944 for engagement by jawsof an appropriate handpiece. While this is the least expensive way tomanage ampules 21, it is also the most likely to risk contaminationand/or accidental spilling onto the floor.

FIG. 16 illustrates an ampule 21 being extracted from auto-feed magazine890 (FIG. 14) by injector 200 shown in FIG. 9. Ampule 21 could also begrabbed and extracted from folding magazine 820 (FIG. 13) or crate 940(FIG. 15) with the same injector jaw assembly.

FIG. 17 illustrates an in-line version of auto-feed magazine 890 shownin FIG. 14 and is geometrically similar to stationary magazine 820 shownin FIG. 13 d. This in-line type magazine is the preferred embodiment insome cases because it reduces the amount of handling of the ampulestrip, i.e., the packaging alignment is similar to the way it will beinserted into the filling station, and after that, into the magazineitself. This is easier and faster than trying to coil the ampule stripfor use with the rotating magazine shown in FIGS. 14 a and 14 b. Thein-line magazine is also easier to hold and equally convenient for wristmounting if so desired. Thus, FIG. 17 shows in-line magazine 950 havinga housing 952 comprised of a base 954 and a cover 956 connected to base954 by an integral hinge 958. A spring wound take-up spool 960 (usingnegator spring 900) is disposed in an appropriately figured compartment962 of housing 952. A longitudinally extending dividing wall 964 extendsbetween compartment 962 and an end 966 of housing 952. A path for anampule strip is defined between the opposite side surfaces of dividingwall 964 and the inside surfaces of opposing side walls 968, 970 of base954. An ampule strip such as strip 800 in FIG. 12 a could be used. Itextends from a base end and extends to a connecting end attached tospool 960. A nylon pull-cord 972 for winding up negator spring 900 isshown in this FIG. 17, and is the same as that described above formagazine 890 in FIGS. 14 a, 14 b. In both auto-feed magazines 890, 950,the housing can also be transparent for a visual appraisal of the numberof ampules remaining. A funnel-shaped opening 973 is provided forpresenting the proximal end 717 of ampules 21 for grasping by the jawsof an injector.

FIG. 18 a is another embodiment of the rotating auto-feed magazine.However, rotating auto-feed magazine 980 as shown has a housing with acover 984 and a base 986. Cover 984 has a set of V-like rails 988 tovirtually guide the injector nose into a funnel-shaped opening 990 wherean ampule 21 appears for being grasped or retrieved with little or novisual contact by the user. For this reason, this embodiment is called a“noseeum” model; however, ampules 21 are grabbed by the jaw assembly thesame as that described for the other magazine embodiments. It is notedthat the “noseeum” feature is very important in high-speed procedureswhere it was found that delivery efficiency is greatly improved when thevaccinator is able to keep his/her eyes on the next patient rather thanlooking around for the next ampules 21.

FIG. 18 b illustrates magazine 980 in the released position from amounting bracket 989, and FIG. 18 c shows magazine 980 in the securedposition in the mounting bracket 989. Mounting bracket 989 can be anyappropriate bracket in the market.

FIG. 19 is an illustration of an ampule filling station 990 describedabove and will be included in injection kit 10 of FIG. 1. The purpose offilling station 990 is to accelerate the ampule fill rate. It could havea fill rate capacity in excess of 600 ampules per hour in order to keepup with patient throughput, or several filling stations with slower fillrates could be used simultaneously. A more likely scenario would be touse a slower fill rate filling station to pre-fill a large quantity ofampules before the start of vaccine administration. It is preferred thateach ampule be addressed individually in a serial manner (as opposed tocollectively in a parallel manner) to minimize maintenance/cleaning ofthe fluid path, reduce the chance of entrapping air bubbles, and reducethe possibility of contamination.

Filling station 990 includes a housing 991 and a manual fluid transferhandle 992. A magazine 993, which could be one of those discussed above,receives ampules 21 on a strip, such as ampule strip 800 shown in FIG.12 a. A shroud 994 is used to cover magazine 993 in order to reduce thelikelihood of contamination. After magazine 993 housing empty ampules isinserted into the filling station at access port 997, injectate isforced into ampules 21 one by one upon the actuation of handle 992,which effects the filling of ampules 21 from injectate contained insyringe 998. The full magazine 995 exits the filling station at an exit996 of filling station 990. The filled magazine 995 is again coveredwith a shroud 994 when it exits from filling station 990.

In an alternate embodiment, ampules can be provided in strips 800 thatinterface with filling station 990 directly. After being filled in muchthe manner as described above, strips 800 of filled ampules may then beplaced immediately into magazine 993 or placed into cold storage to beinstalled in magazines just before use. While considering the variousmeans for filling ampules 21 for mass immunization campaigns, and asmentioned above, the assumption is made that the vaccine is available ina 50-dose vial of lyophilized vaccine with the associated 30 ml vial ofdiluent. Single-dose or ten-dose vials may also be used, but theincreased frequency of swapping vials will slow the overall fillingprocess accordingly. The possible means for filling include: 1) forcinginjectate through output orifice 710 as illustrated with filling station990 shown in FIG. 19, 2) forcing injectate through the piston (similarin nature to that discussed below with reference to FIG. 20 a, whichrefers to the use of lyophilized vaccine), and 3) pulling injectatethrough orifice 710 by drawing on the piston. Use of a piston tofacilitate filling from a filling station (as opposed to forcing thevaccine in through the orifice when using the filling station) posesseveral problems. The small diameter of the piston (0.186 in, 4.72 mm),coupled with the lack of an ampule plunger in the injection systemdisclosed, makes it very difficult to create an appropriate interface tothe filling station. The precision needed to interface with a smallercomponent could very well lead to problems in the rougher treatmentexpected in the field. This concept was therefore not included infilling station 990 of FIG. 19 as discussed above, but it does fallwithin the scope of the invention. The orifice at distal end 710 ofampule 21 provides for a more user-friendly interface due to theincreased outside diameter of ampule 21 (0.375 in, 9.53 mm). Fillingstation 990 therefore preferably uses distal end 710 of ampule 21.Forcing the injectate into ampule 21 by use of a large syringe 998 asshown in FIG. 19, or by pressurizing the vial containing thereconstituted vaccine have all been considered. Pumping air into thevial (i.e., avoiding transfer of syringe 998) to pressurize the contentscould be accomplished via a simple ball type pump (bulb) such as thatfound on a sphygmomanometer or via a mechanically actuated syringe pump.A more complicated system utilizing a motor driven pump, with manualoverride, is possible but would add cost, weight and complexity to theportable system. The main difficulty in using the vial comes in thevalving required to control flow of air into the vial and flow ofinjectate out of the vial. In addition, how to control and monitor thepressure within the vial is at issue. The complexity of valving, coupledwith the need for pressure control, favors a standard large syringe 998as a solution for filling the ampules, and this is what is shown in FIG.19. The syringe requires no valving, external pressurization, orpressure monitoring, to provide an accurate fill. In addition, andimportantly, standard practice uses large syringes to mix the diluentwith the lyophilized vaccine, and the same syringe 998 could then beused to then fill the ampules. A custom interface is provided for thesyringe/vial interaction (i.e. for mixing diluent with lyophilizedvaccine and for drawing mixed vaccine into syringe 998), or users couldcontinue using standard needles to mix vaccine and to draw vaccine fromthe vial into the syringe. When filling ampules 21 from the syringes,advancement of the syringe plunger is accomplished via a simple leveraction 992, or alternatively, a more, complicated motor driven means.Many of these issues were addressed when settling on the filling stationof FIG. 19 and have been eliminated with the use of ampules 21 that arepre-filled with liquid vaccine as described, or much better, thelyophilized pre-filled ampules 21 as described for FIGS. 20 a-20 fbelow.

The series of ampule and magazine configurations illustrated in FIGS. 20a-20 f are directed to the very important concept of thevaccine/medication manufacturers pre-filling the ampules prior toshipping them to the user. Pre-filling provides the promise for numerousimprovements in some very important healthcare concerns, especially soin campaigns for mass immunization. Two of the most difficultconsiderations are time and sanitation, both of which are nicelyaddressed with the concepts disclosed. Time for preparation is a crucialfactor for an immunization campaign in the difficult conditions oftenfound in third world countries, and sanitation is virtually non-existentin some of these situations where misuse and mishandling runs rampant.This is especially true when it comes to handling the syringes andvaccine both before and after the injections are given.

The concepts found in FIGS. 20 a-20 f also address the problems thathave long existed for pre-filled ampules. Plastic, for example, has longbeen banned for vaccine storage because of the possibility of leaching.While recent findings indicate that some of the higher-grade medicalplastics may be satisfactory for long-term storage for vaccines, finalapproval remains to be seen; consequently, the concepts described inFIGS. 20 a-20 f deal with both plastic storage and the long-acceptedmeans of storing in glass. The mixing ampules shown in FIGS. 20 a-20 fillustrate both a one-way valve and a frangible interface to provoke themixing action; however, it has been shown that a one-way valve as shownin FIG. 20 a with a small retaining pressure, will be effective forallowing the mixing action in place of a frangible interface as shown inthe other figures, i.e., FIGS. 20 d, 20 e and 20 f. It is also notedthat in each of the diagrams shown in FIGS. 20 a-20 f, the lyophilizedvaccine is shown as a small pill-type member for illustrative purposes;however, in reality, the vaccine will totally fill the space to assure aminimum of air in the compartment. By the same token, while it has beenpointed out in earlier discussion that filling the ampules through thefront end with liquid vaccine will virtually eliminate the introductionof air into the injectate chamber, the same is not true for the case ofpre-filled lyophilized vaccine where a very small amount of air willinevitably exist; consequently, following the mixing action for each ofthese cases, some form of minimal venting may be needed.

FIG. 20 a illustrates an ampule 1000 that contains lyophilized vaccine1001 and its diluent, the two being separated by a piston 1002 having apiston head 1004 with a one-way valve 1006 in the direction of an exitnozzle 1018. The embodiment shown uses umbrella valve 1006 that willopen (as shown in dotted lines) when piston 1002 is pulled verticallydownward in the figure, wherein a diluent 1010 is forced upward, throughthe fluid flow path channel, past the valve, and into the lyophilizedportion of the chamber for immediate mixing. Piston 1002 has a ring seal1012 for sealing against fluid flow around the periphery of piston 1002.The injection is given by first removing a cap 1016 that seals anorifice 1018, slightly advancing the now sealed piston head 1004 toexpel any air, and then fully pushing piston 1002 forward for theinjection, wherein umbrella valve 1006 will seal throughput ports 1020that were used for the mixing action. Cap 1016 shown on exit port 1018is needed to prevent air from being pulled into ampule 1000 and must beremoved to vent air and before an injection is given. Piston 1002 has apiston rod 1022 which is designed so that the MIT injector ram canoptionally grab and pull it back during motor reversal when armingoccurs. A seal 1024 is provided around an orifice 1026 in ampule 1000 toprevent leakage through orifice 1026. Alternatively, rod 1022 can beeliminated if a small piece of magnetic material, such as a magneticdisk, is attached to the proximal side 1028 of piston head 1004. Astrong magnet on the injector ram (such as ram 403) will make contactwith the metal disk when ampule 1000 is inserted; consequently, pistonhead 1004 will follow the ram in the reverse direction when armingoccurs. After an injection, piston 1002 must be locked in the forwardposition as described earlier (see FIG. 10 a), thus allowing a smallreverse jog of the ram to separate the two for sanitary disposal.

FIG. 20 b has only lyophilized medication 1001 in the forward or distalpart of ampule 1000. In this case, diluent 1010 is forced into exitnozzle 1018 from a filling station, while at the same time forcingpiston 1002 to the proximal end of ampule 1000. As before, the need forventing is likely, and a rapid forward push on piston 1002 will provokethe injection.

FIG. 20 c again has lyophilized vaccine 1001 in the forward part ofampule 1000; however, in this case, an appendage 1030 containing diluent1010 is attached to exit nozzle 1018 with an appropriate seal 1032. Whenan appendage piston 1034 is forced downward, diluent 1010 will flow intothe chamber for immediate mixing while simultaneously pushing injectorpiston 1002 to the proximal end of ampule 1000. This model is ideallysuited to the mixing magazine system described in FIG. 20 e below.

FIG. 20 d has both lyophilized vaccine 1001 and diluent 1010 in anappendage 1036 connected to the front end; however, the two areseparated by a very thin, frangible interface 1038, or alternatively, aone-way valve. As soon as pressure is applied to an appendage piston1040 and interface 1038 is broken, diluent 1010 is forced into the lowerchamber to provoke immediate mixing in appendage 1036, and at the sametime, forcing the mixed fluid through nozzle 1018 to force injectionpiston 1002 to the proximal end of ampule 1000. This technique is alsoideally suited to the mixing magazine of FIG. 20 e.

FIG. 20 e illustrates a complete mixing/shipping magazine that houses amultitude of pre-filled ampules. This technique could be housed in a lidfor the stationary folding magazine and/or the auto-feed magazinesdescribed earlier. As such, the force needed to provoke the mixingaction will require that the lid be collapsible into the lowerstationary portion of the magazine. This type of magazine will ideallyserve as a shipping container to further reduce the risk ofcontamination due to ampule handling, the need for which is virtuallyzero. The appendage for each ampule is similar to that described forFIG. 20 d; however, in this case, the appendage is shown as a bellowsassembly. Either type of collapsible appendage is suitable forexercising the techniques described.

Still referring to FIG. 20 e, a filling system 1100 is shown. It has aforce transfer member 1102 for collapsing pleated walls 1104 of storageunit 1103 to collapse a chamber 1106 holding diluent 1010 above afrangible interface 1138, and lyophilized medication 1001 belowinterface 1138. This applies to each of N filling stations filled by theoperation of member 1102. Each ampule 1000 has a body portion withpiston 1002 having wall engaging seals 1012. Storage unit 1103 isconnected to exit nozzle 1018 having a seal 1032 to prevent leakage.Upon the application of sufficient downward force on member 1102, themixing diluent 1010 and lyophilized medication 1001 flow through exitorifice 1018, forcing piston 1002 downward as shown by the arrow to fillthe ampule. A cap could optionally be applied over nozzle or orifice1018 to close ampule 1000 until an injection is made.

FIG. 20 f illustrates an ampule 1200 that contains a lyophilized vaccine1202 and its diluent 1204, and in that regard is similar to FIG. 20 a.However, in this case, the separation is a very thin, inexpensivefrangible barrier 1206 that eliminates the cost of an appendage and/orthe piston with the one-way valve. A piston 1210 having an annular seal1212 is provided. Barrier 1206 is held in place by a sliding seal 1208which is used to properly locate frangible barrier 1206 in ampule 1200.Force on ampule piston 1210 will cause barrier 1206 to fracture (or aone-way valve to open) and the mixing action occurs. As soon as mixingis complete and the ampule is full of liquid, a sealing cap 1214 can beremoved, whereupon the sliding seal 1208 on barrier 1206 will move withpiston 1210 as it reaches barrier 1206 and completes the injectiontransition through exit port 1216.

While the examples described for the procedures depicted in FIGS. 20a-20 f illustrate a direct pushing force to provoke the mixing action, atwisting motion for advancing a threaded interface could also be used tofacilitate the mixing action.

Finally, it should be noted that the conventional jet injector orificesshown in all of the above descriptions can be replaced with a perforatorexit nozzle as disclosed in U.S. Pat. No. 6,056,716. Perforator deliveryhas been extensively experimented with by the inventors over a number ofyears and has been shown to allow for lower jet pressure, painlessdelivery because the jet stream begins from just inside the skin, whicheliminates the need for the high-speed jet velocity required forcrossing the barrier of fully exposed skin. Protection against sharpsinjury to the healthcare workers remain a concern; however, safety isrealized by hiding the perforator before the injection, and having theinjector itself destroy the perforator after the injection. Severalmethods are shown to be effective, one being where the perforator isextended through a tight fitting exit port of a compressible, protectivefront end that becomes an off axis shield after the perforator is drawnback into the protective housing, i.e., as described for FIGS. 8 a and 8d. In another approach, an off-axis, exit hole on a rotatable disklocated at the exit nozzle will automatically rotate after the injectionto therefore crush and disable the perforator to the point where it isvirtually impossible to do any damage. Another tremendous advantage forusing this low-pressure technique is the very low cost for a thin-walledampule. The inventors have shown over the course of many years ofexperimentation that pressures of anywhere from 200 to 1000 psi areeffective for virtually any type of injection, the preferred pressuredepending on the patient, location for the injection and the requireddepth for the delivery (i.e., intradermal, subcutaneous orintramuscular). Because of this, the use of low cost, thin-walled glassis also possible, since the inventors have also shown that the low costglass ampules that are readily available will not fracture until exposedto pressures in excess of 1500 psi. Consequently, glass ampules forhousing the vaccines for long term storage is a realistic goal for thepre-filled techniques described if perforator delivery is used.

The invention has been described in detail, with particular emphasis onthe preferred embodiment thereof, but variations and modificationswithin the spirit and scope of the invention may occur to those skilledin the art to which the invention pertains.

1. A hypodermic injector for injecting fluid from an ampule loaded insaid injector from a plurality of ampules in sequence, each ampulehaving a sealed condition for containing injectate in a sealed containerand an empty condition where the injectate was discharged from theampule without the necessity of human contact with the ampule before orafter an injections, said injector comprising: a grasping mechanismhaving a grasping condition for grasping an ampule and holding theampule to receive an injectate discharge force, and an open condition,said grasping mechanism comprising: gripper jaws having a closedposition for gripping an ampule inserted in said grasping mechanism andan open position; gripper jaw moving means actuable for moving saidgripper jaws between the closed position; and actuating means foractuating said gripper jaw moving means to move said gripper jaws fromthe open position to the closed position; a plunger device movable froma set condition to a discharge condition for applying discharge force toan ampule in the sealed condition gripped in said gripper jaws to ejectinjectate from the ampule to render the ampule in the empty condition; afirst biasing device having a cocked condition for storing a biasingforce in said device and a released condition, said first biasing devicedischarging force to said plunger device to move said plunger devicefrom the set condition to the discharge condition in response to themovement of said biasing device from the cocked condition to the releasecondition; a first cocking mechanism for moving said first biasingdevice from the release condition to the cocked condition; a releasemechanism actuatable for releasing said first biasing device from thecocked condition to the released condition to effect the movement ofsaid plunger device from the set condition; an ejector mechanism forejecting an empty ampule from said grasping mechanism when said ejectormechanism is in the open condition, wherein said ejector mechanismcomprises: ejecting means movable from a set condition to an ejectingcondition for ejecting an ampule from said gripper jaws when saidgripper jaws are in their open position without requiring the user ofsaid injector to touch the ampules; a second biasing device releasablefrom a cocked condition to a release condition to drive said ejectingmeans to the ejecting condition to eject the ampule; and a secondcocking mechanism for moving said second biasing device from thereleased condition to the cocked condition.
 2. A hypodermic injectoraccording to claim 1 wherein said second cocking mechanism moves saidsecond biasing device to the cocked condition in response to the loadingof an ampule into said injector.
 3. A hypodermic injector according toclaim 1 wherein said ejector mechanism comprises: a release member fordischarging said second biasing device from the cocked condition, saidrelease member being operable from the group consisting of manuallyoperable or automatically operable.
 4. A hypodermic injector accordingto claim 1 and further including a motor having a drive shaftoperatively connected to said first cocking mechanism, said drive shaftbeing rotatable in one direction to cause said first cocking mechanismto assume the cocked position from the release position to move saidfirst biasing device from the release condition to the cocked condition,and automatically rotatable in a reverse direction to reset said driveshaft for the next operation to cause said first cocking mechanism toassume the cocked condition.
 5. A hypodermic injector according to claim1 wherein said grasping mechanism assumes the open position when noampule is grasped by said grasping mechanism, and wherein said graspingmechanism includes a disabling device for disabling said plunger devicefrom moving from the set condition when no ampule is in said graspingmechanism and said grasping mechanism is in the open condition.
 6. Ahypodermic injector according to claim 1 wherein said hypodermicinjector further includes both a remote motor, and a coupling mechanismfor operatively coupling said motor to said first cocking device, and ahandpiece with a housing for containing said grasping mechanism, plungerdevice, first biasing device, first cocking mechanism, releasemechanism, ejector mechanism and second cocking mechanism.
 7. Ahypodermic injector according to claim 1 wherein the ampules have anouter wall with an interior chamber for containing the injectate, aproximal end and a distal end with an orifice in the distal end throughwhich injectate can flow, the chamber extending between the distal endand the proximal end, and a piston movable from the proximal end towardsthe distal end to force injectate from the chamber through the orifice,wherein said injector further includes a motor having a drive shaftoperatively connected to said first cocking mechanism, said drive shaftbeing rotatable in one direction to cause said first cocking mechanismto assume the cocked position from the release position, and said motorshaft being operatively connectable to the ampules and being rotatablein the reverse direction to draw the piston from the distal end of theampule to the proximal end of the ampule to enable filling of the ampulewith the injectate through the orifice.
 8. A hypodermic injectoraccording to claim 1 and further including a magazine for sequentiallypresenting an ampule to be grasped by the grasping mechanism fromampules held in sequence in a strip of ampules, said magazinecomprising: a housing having a holding region for holding a strip ofampules, a presenting region for making an ampule accessible to saidgrasping mechanism and walls for guiding a strip of ampules from saidholding region in sequence to said presenting region; a take-up spoolfor taking up portions of the ampule strip after ampules have beenwithdrawn from the strip by said grasping mechanism; and a drivingdevice for moving said take-up spool to receive the portions of theampule strip after ampules have been withdrawn from the strip.
 9. Ahypodermic injector according to claim 8 wherein said housing comprises:an access wall having access surfaces defining an opening to saidpresenting region wherein said grasping mechanism can grasp an ampule insaid presenting region and withdraw the ampule from said magazine.
 10. Ahypodermic injector according to claim 8 wherein said walls define acurved, generally helical path for the ampule strip, wherein the ampulestrip following the outermost part of said path locates the lead ampulein said presenting region to be grasped by said grasping mechanism,prior to the disposition of the ampule strip having had the ampulewithdrawn therefrom on said take-up spool.
 11. A hypodermic injectoraccording to claim 10 wherein said magazine comprises: a base portionhaving said walls extending therefrom, said walls further defining acompartment for holding said take-up spool; and a cover portion having afunnel-shaped opening to said presenting area from which an ampule onthe ampule strip extends from said presenting region to be grasped bysaid grasping mechanism.
 12. A hypodermic injector according to claim 8wherein said walls define at least one linear path in said housing forguiding the ampule strip towards said take-up spool, and wherein saidpresenting region is on said linear path adjacent to said take-up spool.13. A hypodermic injector according to claim 12 wherein said wallsdefine at least two parallel linear paths connected by a pathinterconnecting an adjacent end of said paths, wherein the ampule stripis movable along one linear path in one direction and along the adjacentpath in the opposite direction, said linear paths terminating at saidpresenting region adjacent said take-up spool.
 14. A hypodermic injectoraccording to claim 13 wherein said housing comprises: a base portionfrom which said walls extend, said base portion further having a take-upspool compartment for holding said take-up spool; and a cover for saidbase portion, said cover having a funnel-shaped opening for receiving aportion of an ampule in said presenting region to provide access to saidgrasping mechanism to grasp the ampule.
 15. A hypodermic injectoraccording to claim 8 wherein said housing comprises an exterior wallhaving an opening to said presenting region for said grasping mechanismto grasp an ampule in said presenting region, and further comprisingguiding walls for guiding said grasping mechanism to said opening tograsp an ampule.
 16. A hypodermic injector according to claim 1 whereinsaid first biasing device is at least one spring having a biasing forcesufficient to drive said plunger device with enough energy to ejectinjectate at jet velocity.
 17. A hypodermic injector according to claim1 and further including a perforator operatively connected to the ampulefor injecting fluid injectate in response to the movement of saidplunger device from the set condition to the discharge condition, saidfirst biasing device driving said plunger device in an increasing mannerduring an injection process, to increase the discharge force applied bysaid plunger device to increase the pressure in the injectate fluid toincrease the depth of injection in a body being injected as compared tothe depth of injection by an injector having a diminishing dischargeforce.
 18. An ampule for use with a hypodermic injector, said ampulecomprising: a body portion with a proximal end, a distal end and alongitudinal axis extending between said proximal end and said distalend, said body portion having a chamber having a relatively largeopening in said proximal end and terminating before said distal end, andfurther having a relatively small orifice extending between thetermination of said chamber and said distal end; a frangible pistonlocated in said chamber for moving in an injection stroke from saidproximal end towards said orifice to drive injectate between said pistonand said orifice through said orifice; and structure for disabling saidampule upon completion of an injection with said ampule, said structurecomprising apparatus for driving said piston beyond the injection stroketo destroy said piston at said orifice at the completion of an injectionthus rendering said ampule incapable of reuse.
 19. An ampule accordingto claim 18 wherein the hypodermic injector has a ram for pushing saidpiston from said proximal end towards said orifice to drive injectatethrough said orifice, and said ampule disabling structure comprises saidpiston being disabled, said piston being movable in response to theinitial movement of the ram to drive injectate through said orifice, andsaid piston being disabled in response to the further movement of theram to render said ampule inoperative for rendering said ampuleincapable of reuse.
 20. An ampule according to claim 18 and furtherincluding a perforator at the end of said orifice for penetrating theskin of a body being injected to control the injection depth and toreduce the force required to make the injection.
 21. An ampule accordingto claim 20 wherein said ampule disabling structure comprises adisabling device substantially covering said perforator for disablingsaid ampule after an injection has been made using the ampule.
 22. Anampule according to claim 21 wherein said disabling device is acollapsible cover for said perforator having a weakened wall whichcollapses upon the rendering of an injection to render said perforatorinaccessible.
 23. An ampule according to claim 20 wherein saidperforator is the thickness of skin of the person or animals to beinjected at the place of injection, the animals include dogs, cats,pigs, cows, horses, elephants, chickens, turkeys, roosters, geese,lobsters, crabs, goats, camels and sheep.
 24. An ampule according toclaim 23 wherein said perforator has a length of from 1.0 mm to 12.7 mm.25. An ampule for a hypodermic injector, said ampule comprising: a bodyportion having inside surfaces defining a chamber, said body portionhaving an orifice extending to said chamber at one end of the bodyportion defining a path for injectate during an injection; a piston insaid chamber extending between the inside surfaces of said body portion;a portion of said chamber on one side of said piston for initiallyholding lyophilized medication; a portion of said chamber on the otherside of said piston for holding a diluent for the lyophilizedmedication; structure for enabling flow and mixture of the diluent withthe lyophilized medication in response to movement of said piston toprepare injectate to be discharged from said ampule; and structure fordisabling said ampule upon completion of an injection with said ampule.26. An ampule according to claim 25 wherein said structure comprises aone-way valve on said piston for opening when the piston moves in adirection away from said orifice, and closing in response to movement ofsaid piston towards said orifice to effect an injection.
 27. An ampulefor a hypodermic injector, said ampule comprising: a body portion havinginside surfaces defining a chamber, said body portion having an orificeextending to said chamber at one end of said body portion fordischarging injectate during an injection; and a piston located in saidchamber extending between said inside surfaces and defining a cavitybetween said piston and said orifice for receiving lyophilizedmedication; said orifice being able to receive diluent under pressurefor mixing with the lyophilized medication in said cavity to form aninjectate; and said piston being movable away from said orifice inresponse to the entry of diluent into said cavity to enlarge the size ofsaid cavity.
 28. An ampule assembly for a hypodermic injector, saidampule assembly comprising: a body portion having inside surfacesdefining a first chamber, said body portion having an orifice extendingto said first chamber at one end of said body portion defining a pathfor injectate during an injection; an ampule piston in said firstchamber extending between the inside surfaces of said body portiondefining an ampule cavity between said ampule piston and said orifice;and an appendage attachable to said body portion over said orifice, saidappendage including: interior surfaces defining a second chamber; adischarge opening for connection to said orifice in said body portion;an appendage piston extending across an end of said second chamber; anda frangible separator extending across said second chamber and locatedbetween said appendage piston and said discharge opening to define afirst appendage cavity between said separation and said appendagepiston, and a second appendage cavity between said separator and saiddischarge opening; at least one of said second appendage cavity and saidampule cavity being a receptacle for lyophilized medication and saidfirst appendage cavity being a receptacle for diluent, said frangiblecavity rupturing to effect the mixing of the lyophilized medication andthe diluent to form an injectate in response to the application ofsufficient force to said appendage piston, said ampule piston beingmovable in response to the flow of at least one of diluent or injectatethrough said orifice to increase the size of said ampule cavity; andsaid appendage being detachable from said ampule to clear said orifice,and said ampule piston being movable towards said orifice to injectinjectate through said orifice.
 29. An ampule assembly according toclaim 28 wherein said ampule cavity is the receptacle for thelyophilized medication, and the first appendage cavity is the initialreceptacle for the diluent.
 30. An ampule assembly according to claim 28wherein said first appendage cavity is the initial receptacle for thediluent and said second appendage cavity is the initial receptacle forlyophilized medication.
 31. An ampule for a hypodermic injector, saidampule comprising: a body portion having inside surfaces defining achamber, said body portion having an orifice extending to said chamberat one end of said body portion for discharging injectate during aninjection; a piston located in said chamber extending between saidinside surfaces; a frangible separator extending between said insidesurfaces and located between said orifice and said piston to separatesaid chamber into one cavity for holding lyophilized medication and asecond cavity for holding a diluent, said separator being ruptured inresponse to the movement of said piston into one of said cavity whenfilled with one of the lyophilized medication and the diluent to effectmixing of the lyophilized medication and the diluent for ejectingthrough said orifice; and structure for disabling said ampule uponcompletion of an injection with said ampule.
 32. One ampule according toclaim 30 wherein said one cavity is between said orifice and saidseparator, and said second cavity is between said separator and saidpiston.
 33. A magazine for mixing lyophilized medication and diluent inat least one ampule assembly, each assembly having an ampule with a bodyportion defining a first chamber having an inlet and outlet orifice atone end with a piston movable in said first chamber, said magazinecomprising: at least one collapsible storage container being connectableto the orifice, the container having collapsible walls defining acollapsible second chamber and a separator extending across the secondchamber to separate the second chamber into one cavity for holdinglyophilized medication and a second cavity for holding diluent and aforce transfer member for operative connection to said at least onecollapsible storage container for collapsing the collapsible walls ofsaid at least one container in response to the application of asufficient force to said force transfer member to effect the mixing ofthe respective lyophilized medication and diluent in the respectiveampule assemblies, and to fill the respective ampules with the mixedlyophilized medication and diluent through the respective orifices. 34.An arming station for setting an injection spring in a hypodermicinjector to make the injector ready for an injection from a firedcondition to a ready condition, the hypodermic injector having an ampuleholding device for holding an ampule containing an injectate, apparatusfor discharging the injectate upon the impact of a plunger at apredetermined end of the ampule, a plunger device for being driven intothe predetermined end of the ampule to provide the impact to dischargethe injectate, at least one spring having enough spring force upon thetensioning of the spring to a set condition to drive the plunger intothe ampule to provide the impact to discharge the injectate and a springholding device for holding the at least one spring in the readycondition, and a cocking member movable a predetermined amount to setthe injection spring, said arming station comprising: a rearming dockfor holding a fired hypodermic injector in position to have the injectorrearm to the ready condition; a manual device for moving the cockingmember by the predetermined amount to set the injection spring, saidmanual device including a manually movable gripping member for grippingthe cocking member and moving it in response to the manual movement ofthe gripping member.
 35. An arming station according to claim 34 whereinthe cocking member is a draw rod which must be pulled for apredetermined distance to set the injection spring, and said manualdevice includes a device for gripping the draw rod and a lever formoving said gripping device by the predetermined distance to set theinjection spring.
 36. An arming station according to claim 34 andfurther including a pick-up cradle for holding a hypodermic injectorhaving been rearmed to the ready condition pick-up for use as aninjector.
 37. A hypodermic injector for injecting fluid from aninjection chamber having an exit nozzle in a sequential manner, eachinjection, occurring from the chamber without the necessity of humancontact with the exit nozzle, the injection chamber or the injectingfluid, said injector comprising: a plunger device movable from a setcondition to a discharge condition for applying discharge force to theinjection chamber to eject injectate fluid from the chamber; and abiasing device having a drive shaft operatively connected to saidplunger device to move said plunger device from the set condition to thedischarge condition, and for moving said plunger device from thedischarge condition to the set condition.
 38. A hypodermic injectorhaving a supply holding device for holding a supply wherein said supplyincludes a plunger in the supply, said injector having a fluid transferdevice for transferring injectate fluid from a reservoir, said injectorcomprising a device for at least partially withdrawing the plunger fromthe supply to effect the transfer of injectate fluid from the reservoirto the supply, said injector having structure for slowly jogging theplunger towards the discharge condition to expel air from the supply.39. A hypodermic injection system comprising: a handpiece for receivinga cartridge containing an injectate, said handpiece having a cartridgeholding device for holding a cartridge and an injectate discharge deviceactuable for effecting the discharge of injectate from a cartridge heldby said cartridge holding device, a personally-operated arming apparatusremote from said handpiece, and an electrical connector for operablyconnecting said arming apparatus and said injectate discharge device foractuating said injectate discharge device in response to operation ofsaid personally-operated arming device.
 40. A hypodermic injectoraccording to claim 32 wherein said biasing device moves said plungerdevice in an increasing manner during an injection process, to increasethe discharge force applied by said plunger device to increase thepressure in the injectate fluid to increase the depth of the injectionin a body being injected as compared to the depth of injection by aninjector having a diminishing discharge force.
 41. A crate assembly forholding ampules for withdrawal of ampules held in the crate assembly bya hypodermic injector ampule-grasping mechanism in an injectionprocedure, the ampules comprising a generally cylindrical body portionwith a relatively narrow diameter extending from a forward portiontowards a rearward portion and a wider portion having a peak near therearward portion and a tapered rearwardly-extending surface extendingfrom the peak to the rearward end of the ampule, said crate assemblycomprising: a support surface having a series of orifices defined byorifice surfaces having diameters slightly larger than the diameters ofthe forward portion of the ampule to provide sufficient contact betweenthe respective orifice surfaces and the held ampules for holding theampules with the forward end in a respective orifice to prevent theampules from falling out of the orifices during ordinary use of saidcrate assembly during an injection procedure, and the wider portion ofthe ampule extending from said orifices in positions to be grasped by ahypodermic injector having an ampule-grasping mechanism.
 42. Thecombination of a hypodermic injector for use with ampules and a crateassembly, said combination comprising: a hypodermic injector forinjecting fluid from an ampule loaded in said injector from a pluralityof ampules in sequence, each ampule having a sealed condition forcontaining injectate in a sealed container and an empty condition wherethe injectate was discharged from the ampule without the necessity ofhuman contact with the ampule before or after injection, each ampulefurther having a forward portion with a relatively narrow diameter, arearward portion, and a wide peak near the rearward portion and atapered rearwardly-extending surface extending from the peak to therearward portion; and said injector comprising: a grasping mechanismhaving a grasping condition for grasping an ampule without the necessityof human contact and holding the ampule to receive an injectatedischarge force, and an open condition; a plunger device movable from aset condition to a discharge condition for applying discharge force toan ampule in the sealed condition to release injectate from the ampuleto render the ampule in the empty condition; a first biasing devicehaving a cocked condition for storing a biasing force in said device anda released condition, said first biasing device discharging force tosaid plunger device to move said plunger device from the set conditionto the discharge condition in response to the movement of said biasingdevice from the cocked condition to the release condition; a firstcocking mechanism having a cocked position and a release position, saidfirst cocking mechanism to assume the cocked position from the releaseposition for moving said first biasing device from the releasedcondition to the cocked condition; a first biasing device releasemechanism actuatable for releasing said first biasing device from thecocked condition to the released condition to effect the movement ofsaid plunger device from the set condition; an ampule release mechanismfor releasing an ampule in the empty condition from said graspingmechanism in the open condition, said ampule release mechanism includinga release member movable from a set condition to a release condition forengaging and releasing an ampule from said injector, and a secondbiasing device releasable from a cocked condition to a releasedcondition to drive said ampule release mechanism to release the ampule;and a second cocking mechanism for moving said second biasing devicefrom the released condition to the cocked condition; and a crateassembly for holding ampules for withdrawal of ampules held in the crateassembly by a hypodermic injector ampule-grasping mechanism, said crateassembly comprising: a support surface having a series of orificeshaving diameters slightly larger than the diameters of the forwardportion of the ampule for holding the ampules with the forward end in arespective orifice and the wider portion of the ampule extending fromsaid orifices in positions to be grasped by said ampule-graspingmechanism of said hypodermic injector.
 43. An ampule for use with ahypodermic injector, said ampule comprising: a body portion with aproximal end, a distal end and a longitudinal axis extending betweensaid proximal end and said distal end, said body portion having achamber having a relatively large opening in said proximal end andterminating before said distal end, and further having a relativelysmall orifice extending between the termination of said chamber and saiddistal end; and a slidable spool located in said chamber between saidpiston and said proximal end, and a spring device associated with saidspool locking said spool in said chamber against movement towards saidproximal end; said piston being slidable in said chamber from a positionadjacent said orifice to said spool in response to the flow of injectateunder pressure through said orifice; and said spool forcing said pistontowards said orifice by the high-speed impact of a plunger against saidspool to force injectate through said orifice to effect an injection.